Cross country pipelines are usually coated with a corrosion-resistant substance. To protect the coating from damage when the ditch is back filled with excavated material, which may contain large rocks, the pipeline is first covered with fine particles of dirt to serve as a protective padding around the pipeline.
U.S. Pat. No. 5,084,991, issued to Cronk Jr. on Feb. 4, 1992, discloses a system for pipeline padding and is hereby incorporated by reference in its entirety. The disclosed system provides for padding of a pipeline lying in a ditch by separating fine particles from coarse particles in material excavated from the ditch and windrowed along the side of the ditch. As the system moves along the excavated material, a separator drum rotates to lift the material and rotate it. As the material is rotated above the drum, it falls through a screen or between rods which separate the fine materials of the excavated material from the coarse materials.
There is, however, a disadvantage to this system. There are scoop members attached to the drum which are used to lift the excavated material as the drum rotates. The scoop members are attached in very close proximity to the surface of the screen or rods which filter the fines from coarse material during rotation. Due to the close proximity, as the rotating scoop members begin to lift the excavated material, the material is retained between the scoop members and screen surface or rods until the respective scoop member has been rotated upwardly by the drum to the upper portion of the path of rotation, thereby resulting in limited relative movement of the excavated material with respect to the rods or screen surface resulting in less excavated material being filtered during a rotation.
Accordingly, there is a need in the art for an improvement to the system of Cronk, Jr., thereby providing a more efficient and cost-effective pipe padding operation.